The present invention relates to a process of microbiological production of carotenoid compounds. More specifically, the present invention relates to a process of producing carotenoid compounds such as astaxanthin, adonixanthin, xcex2-carotene, echinenone, canthaxanthin, zeaxanthin, xcex2-cryptoxanthin, 3-hydroxyechinenone, asteroidenone and adonirubin.
Carotenoid compounds are natural pigments useful as feed additives, food additives, pharmaceuticals and the like. Especially, astaxanthin has a high industrial value as feed additives such as a color improver for bred fishes, e.g., salmon, trout or red sea bream, and as safe natural food additives. Likewise, adonixanthin is, if its industrial production process is established, promising as food additives, feed additives, pharmaceuticals, etc. Further, xcex2-carotene has been used as feed additives, food additives, pharmaceuticals, etc.; canthaxanthin has been used as food additives, feed additives, cosmetics, etc.; and zeaxanthin has been used as food additives, feed additives, etc. Further, other carotenoid compounds such as echinenone, xcex2-cryptoxanthin, 3-hydroxyechinenone, asteroidenone and adonirubin are also promising as feed additives, food additives, etc. As processes for producing these carotenoid compounds, such methods as chemical synthesis, production by microorganisms, and extraction from natural products are known. For astaxanthin, canthaxanthin and xcex2-carotene, chemically synthesized products have already been commercialized.
Astaxanthin is contained in fishes such as red sea bream, salmon and trout, and in crustaceans such as shrimp, crab, crawfish and krill, and can be obtained through extraction from them. Examples of astaxanthin-producing microorganisms include red yeast Phaffia rhodozyma; a bacterium belonging to the genus Brevibacteriuin (Journal of General and Applied Microbiology, 15, 127, 1969); bacterial strain E-396 (FERM BP-4283) belonging to a novel genus (Japanese Unexamined Patent Publication Nos. 7-79796 and 8-9964; U.S. Pat. Nos. 5,607,839 and 5,858,761); bacterium Agrobacterium aurantiacum (Japanese Unexamined Patent Publication No. 7-184688); and green alga Haematococcus pluvialis (Phytochemistry, 20, 2561, 1981). As processes of chemical synthesis, conversion of xcex2-carotene (Pure Appl. Chem. 57, 741, 1985) and synthesis from C15 phosphonium salts (Helv. Chim. Acta. 64, 2436, 1981) are known.
It is known that Canthaxanthin is contained in certain species of mushrooms (Botanical Gazette, 112, 228-232, 1950), as well as fishes and crustaceans (Carotenoids of Marine Organisms, Journal of the Japanese Society of Fisheries Science, 1978). Examples of canthaxanthin-producing microorganisms include a microorganism belonging to the genus Brevibacterium (Applied and Environmental Microbiology, 55(10), 2505, 1989); a microorganism belonging to the genus Rhodococcus (Japanese Unexamined Patent Publication No. 2-138996); bacterial strain E-396 (FERM BP-4283) belonging to a novel genus (Japanese Unexamined Patent Publication Nos. 7-79796 and 8-9964; U.S. Pat. Nos. 5,607,839 and 5,858,761); and bacterium Agrobacterium aurantiacum (Biosci. Biotechnol. Biochem. 58, 1842, 1994). As processes of chemical synthesis, conversion of xcex2-carotene (J. Amer. Chem. Soc., 78, 1427, 1956) and synthesis from a novel 3-oxo-C15 phosphonium salt (Pure Appl. Chem., 51, 875, 1979) are known.
It is known that adonixanthin is contained in fishes such as goldfish and carp. However, its chemical synthesis is believed to be difficult, and no industrial process for production of adonixanthin has been known. Examples of adonixanthin-producing microorganisms include microorganisms belonging to the genera Flavobacterium, Alcaligenes, Pseudomonas, Alteromonas, Hyphomonas and Caryophanon, respectively (Japanese Unexamined Patent Publication No. 6-165684); bacterial strain E-396 (FERM BP-4283) belonging to a novel genus (Japanese Unexamined Patent Publication Nos. 7-79796 and 8-9964; U.S. Pat. Nos. 5,607,839 and 5,858,761); and bacterium Agrobacterium aurantiacum (Biosci. Biotechnol. Biochem. 58, 1842, 1994).
As processes for producing xcex2-carotene, synthesis from xcex2-ionone (Pure Appl. Chem. 63(1), 45, 1979) and extraction from green or yellow vegetables such as carrot, sweet potato or pumpkin (Natural Coloring Agent Handbook, Kohrin (1979), edited by Editorial Committee of Natural Coloring Agent Handbook) are known. Examples of xcex2-carotene-producing microorganisms include algae belonging to genus Dunaliella, fungi belonging to genus Blakeslea (J. Appl. Bacteriol., 70, 181, 1991); bacterial strain E-396 (FERM BP-4283) belonging to a novel genus (Japanese Unexamined Patent Publication Nos. 7-79796 and 8-9964; U.S. Pat Nos. 5,607,839 and 5,858,761); and bacterium Agrobacterium aurantiacum (FEMS Microbiology Letters 128, 139, 1995).
Echinenone is extracted from natural products, e.g., starfishes such as crown of thorns, internal organs of fishes such as red sea bream, sea urchin, internal organs of crustaceans such as lobster, etc. Examples of echinenone-producing microorganisms include bacterial strain E-396 (FERM BP-4283) belonging to a novel genus (Japanese Unexamined Patent Publication Nos. 7-79796 and 8-9964; U.S. Pat Nos. 5,607,839 and 5,858,761) and bacterium Agrobacterium aurantiacurn (FEMS Microbiology Letters 128, 139, 1995).
As processes for producing zeaxanthin, chemical synthesis starting from an optically active hydroxy ketone obtained by asymmetric reduction of oxoisophorone (Pure Appl. Chem., 63(1), 45, 1991) and extraction from corn seeds (Biopigments, 1974, Asakura Shoten) are known. Examples of zeazanthin-producing microorganisms include a bacterium belonging to the genus Flavobacterium (Carotenoids, In Microbial Technology, 2nd Edition, Vol. 1, 529-544, Academic Press, New York); bacterial strain E-396 (FERM BP-4283) belonging to a novel genus (Japanese Unexamined Patent Publication Nos. 7-79796 and 8-9964; U.S. Pat. Nos. 5,607,839 and 5,858,761) and bacterium Agrobacterium aurantiacum (FEMS Microbiology Letters 128, 139, 1995).
However, the above-described production processes have various problems. For example, safety is not assured for the synthesized products; production by microorganisms is low in productivity; and extraction from natural products requires high cost. In the production of astaxanthin, for example, extraction from natural products such as krill or crawfish requires high cost since the content of astaxanthin is extremely small and yet the extraction is difficult. Red yeast Phaffia rhodozyma has a low growth rate, produces only small amounts of astaxanthin, and has a hard cell wall that makes the extraction of astaxanthin difficult. Thus, industrialization of astaxanthin production using this yeast is problematic. Green alga Haemnatococcus pluvialis also has many problems. Its growth rate is extremely low; this microorganism is easily contaminated; and extraction of astaxanthin therefrom is difficult. Thus, industrialization using this microorganism is problematic.
Bacterial strains E-396 (FERM BP-4283) and A-581-1 (FERM BP-4671) belonging to a novel genus (Japanese Unexamined Patent Publication Nos. 7-79796 and 8-9964; U.S. Pat. Nos. 5,607,839 and 5,858,761) have a number of advantages, e.g., high productivity, high growth rate, and easy extraction. However, since these microorganisms produce a plurality of carotenoid compounds such as astaxanthin, adonixanthin, xcex2-carotene, echinenone, canthaxanthin, zeaxanthin, xcex2-cryptoxanthin, 3-hydroxyechinenone, asteroidenone and adonirubin simultaneously, production ratios of these compounds vary from culture to culture, and it has been difficult to produce pigments at stable ratios. When the resultant pigment mixture is used in animal feeds, etc. as a color improver, the effect of color improvement varies rather widely. This has been an obstacle to commercial production of pigments using these microorganisms.
Thus, a process for stably producing carotenoid compounds at constant ratios has been desired.
The present invention has been made in view of such circumstances. It is an object of the present invention to control the production ratios of carotenoid compounds and to provide a process for stably producing carotenoid compounds at such controlled, specific ratios.